Human Body Lecture Exam 4 (Renal Physiology)

Front 1

What is the glomerular pressure?

Back 1

higher than other capillaries
around 55 mm Hg

Front 2

What is the normal capillary pressure?

Back 2

around 18 mm Hg

Front 3

Why is glomerular filtration so much more efficient than capillary beds? (2)

Back 3

1000 times more permeable to water and solutes
has a combined SA equal to the SA of the skin

Front 4

How long does it take to filter the entire plasma?

Back 4

22 minutes

Front 5

filtrate

Back 5

blood minus RBCs, WBCs, platelets, and large plasma proteins

Front 6

Net Filtration Pressure (NFP)

Back 6

glomerular hydrostatic pressure - (colloid osmotic pressure + capsular hydrostatic pressure)
around 10 mm Hg

Front 7

Glomerular Filtration Rate (GFR) - Definition

Back 7

total amount of filtrate formed per minute by the kidneys
directly proportional to NFP

Front 8

GFR average value

Back 8

around 125 mL per min =
180 L per day (47 gallons)

Front 9

How little does the glomerular hydrostatic pressure have to drop to stop filtration

Back 9

only 18%

Front 10

What is the range of arterial pressures that intrinsic autoregulation has to regulate?

Back 10

between 80 and 180 mm Hg

Front 11

Intrinsic Autoregulation

Back 11

regulates GFR
Myogenic Mechanism
Tubuloglomerular Feedback Mechanism

Front 12

Myogenic Mechanism

Back 12

tendency of smooth muscle to contract when stretched
afferent arterioles contract when B.P. is too high in response to being stretched

Front 13

Tubuloglomerular Feedback Mechanism

Back 13

responds to filtrate NaCl concentration and releases chemical in response causing the afferents to constrict/dilate

Front 14

Extrinsic Autoregulation

Back 14

Sympathetic Nervous System (neural)
Renin-Angiotension Mechanism (hormonal)

Front 15

Sympathetic Nervous System (3)

Back 15

causes afferent arteriole constriction
shunts blood to other vital organs in stress or emergency
stimulates the release of renin

Front 16

Renin-Angiotension Mechanism (hormonal) (3)

Back 16

JG cells in juxtaglomerular apparatus release renin (an enzyme)
renin helps to produce angiotension II
stabilizes BP in 5 ways

Front 17

Reabsorption (definition)

Back 17

movement of substances from the filtrate in renal tubules into blood of peritubular capillaries (mostly in proximal convoluted tubule)

Front 18

How much filtrate is reabsorbed in 24 hours?

Back 18

178 - 179 liters

Front 19

Transcellular Route

Back 19

fatty acids (lipid soluble substances)

Front 20

Paracellular Route

Back 20

cations (K+, Ca 2+), urea (small size), Cl-

Front 21

Secondary Active Transport

Back 21

Does NOT use ATP
the active transport of Na+ causes a concentration gradient for Na to from lumen into the cells

Front 22

What moves by secondary active transport?

Back 22

Na, and other solutes with co-transport:glucose, amino acids, lactase, vitamins

Front 23

Transport Maximum (Tm) (2)

Back 23

determined by the number of carrier molecules available
when carries are saturated, excess is excreted

Front 24

Where does reabsorption occur?

Back 24

ALL region of the renal tubule
most in proximal portion

Front 25

Secretion

Back 25

blood - filtrate
involves passive and active processes
occurs mainly in PCT

Front 26

One Example of Secretion

Back 26

K+ is actively secreted into collecting ducts under the influence of aldosterone

Front 27

What is the crucial kidney function

Back 27

to maintain stable water concentration in ECF - 300 milliosmoles

Front 28

countercurrent mechanism

Back 28

multiplier + exchanger
establishes AND maintains an osmotic gradient in the medulla (IF)

Front 29

Countercurrent Multiplier

Back 29

ESTABLISHES gradient
flow of filtrate through loop of Henle of the juxtamedullary nephrons

Front 30

Countercurrent Exchanger

Back 30

MAINTAINS gradient
flow of blood through the vasa recta vessels

Front 31

What else contributes to high osmolarity in the deep part of the medulla?

Back 31

the diffusion of urea out of the collecting ducts

Front 32

How low can the concentration of urine be?

Back 32

70 mOsm

Front 33

antidiuretic hormone ADH (4)

Back 33

is the key to concentrating urine
produced by hypothalamus
stored in posterior pituitary
causes water to be reabsorbed

Front 34

facultative water reabsorption

Back 34

water reabsorption that is dependent on ADH

Front 35

Micturition

Back 35

urination; expulsion of urine

Front 36

detrusor muscle

Back 36

a thick muscular layer of detrusor muscle

Front 37

internal urethral sphincter

Back 37

smooth muscle (involuntary control)
contraction opens it, relaxation closes it

Front 38

external urethral sphincter

Back 38

skeletal muscle (voluntary)

Front 39

What happens to infant around 2-3 years old?

Back 39

the pontine (pons) storage reflex overrides the simple spinal reflex

Front 40

Pontine Storage Reflex (5)

Back 40

1. stretch receptors send afferent signals
2. increase sympathetic, decrease parasympathetic
3. inhibit detrusor muscle
4. close internal sphincter
5. stimulate contraction of external

Front 41

Pontine Micturition Reflex

Back 41

-occurs when about 200mL of urine has accumulated
-afferent signals go to the micturition center of the pons and INCREASE parasympathetic, DECREASE sympathetic

Front 42

What causes you to have the urge to void

Back 42

contraction of the detrusor muscle during the pontine micturition reflex